比例框架 Aspect Frames

GtkWidget *gtk_aspect_frame_new( const gchar *label,
                                 gfloat       xalign,
                                 gfloat       yalign,
                                 gfloat       ratio,
                                 gboolean     obey_child);

void gtk_aspect_frame_set( GtkAspectFrame *aspect_frame,
                           gfloat          xalign,
                           gfloat          yalign,
                           gfloat          ratio,
                           gboolean        obey_child);

#include <gtk/gtk.h>
   
int main( int argc,
          char *argv[] )
{
    GtkWidget *window;
    GtkWidget *aspect_frame;
    GtkWidget *drawing_area;
    gtk_init (&argc, &argv);
   
    window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    gtk_window_set_title (GTK_WINDOW (window), "Aspect Frame");
    g_signal_connect (G_OBJECT (window), "destroy",
	              G_CALLBACK (gtk_main_quit), NULL);
    gtk_container_set_border_width (GTK_CONTAINER (window), 10);
   
    /* 创建一个比例框架，将它添加到顶级窗口中 */
   
    aspect_frame = gtk_aspect_frame_new ("2x1", /* label */
                                         0.5, /* center x */
                                         0.5, /* center y */
                                         2, /* xsize/ysize = 2 */
                                         FALSE /* ignore child's aspect */);
   
    gtk_container_add (GTK_CONTAINER (window), aspect_frame);
    gtk_widget_show (aspect_frame);
   
    /* 添加一个子构件到比例框架中 */
   
    drawing_area = gtk_drawing_area_new ();
   
    /* 要求一个200×200的窗口，但是比例框架会给出一个200×100
     * 的窗口，因为我们已经指定了2×1的比例值 */
    gtk_widget_set_size_request (drawing_area, 200, 200);
    gtk_container_add (GTK_CONTAINER (aspect_frame), drawing_area);
    gtk_widget_show (drawing_area);
   
    gtk_widget_show (window);
    gtk_main ();
    return 0;
}